Gate device

ABSTRACT

The invention relates to a gate device ( 50 ) for use in conveying devices ( 10 ) for the automatic charging of small-sized solid fuels ( 3 ), especially wood pellets, characterized by a chamber ( 52 ) which is movable by means of a slide element ( 53 ), comprising a filling opening ( 51 ) and an outlet opening ( 56 ), with the slide element ( 53 ) releasing the filling opening ( 51 ) for filling the chamber ( 52 ) with solid fuel ( 3 ) in the filling position while the outlet opening ( 56 ) is closed, and the slide element ( 53 ) closing the filling opening ( 51 ) in a second position by moving the chamber ( 52 ) while simultaneously the chamber ( 52 ) can automatically be discharged via the outlet opening ( 56 ) which is released in the second position.

The invention relates to a gate device and a conveying device for the automatic charging of small-sized solid fuels, especially wood pellets, and a method for this purpose.

In order to pneumatically fill a fuel hopper attached to a heat generator, especially heating furnace, numerous gate devices have become known which are arranged between the fuel hopper and a second fuel storage container or storage space. The solid fuel, and especially wood pellets, is conveyed in a fuel separator from the storage space by means of a pneumatic conveying device and thereafter introduced into the fuel hopper by means of a rotary valve working in rotary operation and via screw conveyors. The rotary valve acts here as a separating element in order to interrupt a connection between fuel storage chamber and heat generator, so that no hot combustion gases from the furnace can reach the fuel storage chamber. Such a rotary valve is disclosed in AT 501.790 A1.

The disadvantageous aspect in the rotary valve is its complex design in the form of a rotary machine. Moreover, the rotary valve merely acts as a security-related device and does not have any suitable conveying property for filling a fuel hopper, so that for example the screw conveyor devices need to be connected subsequently to the rotary valve. This leads to a complex design of the conveying device, which in addition requires much space.

Further feeding devices are also disclosed in DE 31 32 8149 A1 for example. The security-relevant aspects were not taken into account in this apparatus. DE 1 025 598 and DE 355 493 each describe feeding apparatuses to furnaces. There is also no interruption provided between combustion chamber and fuel storage chamber in these systems either.

It is therefore the object of the invention to provide a conveying device for pellet-like and small-sized solid fuels which are characterized by a compact design.

This object is achieved in accordance with the invention by a gate device of the kind mentioned above in such a way that a chamber which is movable by means of a slide element between a filling position and a discharging position is provided with a filling opening and an outlet opening, with the slide element releasing the filling opening for filling the chamber with solid fuel in the filling position while the outlet opening is closed, and the slide element closing the filling opening in the discharging position while simultaneously the chamber can automatically be discharged via the outlet opening which is released in the discharging position. This gate device fulfils on the one hand the safety-related requirement that no hot fuel gases from the furnace may reach the fuel storage chamber, and acts on the other hand simultaneously as a conveying device which conveys the solid fuel to a fuel storage chamber of a furnace for example. Two different tasks are thus fulfilled by one component, which ensures that a compact design of the conveying device is achieved.

In a preferred embodiment of the invention, a fuel separator is arranged at the filling opening of the chamber which conveys the solid fuel via a respective conveying device preferably in a pneumatic manner into the chamber of the gate device. It is understood that other conveying devices could be provided which are capable of filling the chamber of the slide element with solid fuel.

In a further embodiment of the invention, a fuel storage container of a furnace is arranged at the outlet opening of the chamber. It is especially preferable in this respect that the longitudinal axis of the gate device intersects the longitudinal axis of the fuel storage container under an angle of 35° to 60°. This inclined arrangement of the gate device on the fuel storage container comes with the advantage that complete discharging of the chamber into the fuel storage container is ensured.

The movement of the slide element preferably occurs via a crank drive, with the slide element being connected to the crank drive via a connecting rod. This type of drive is especially advantageous for a compact configuration of a conveying device.

The above object is further achieved by a conveying device for the automatic feeding of small-sized solid fuels, especially wood pellets, with a gate device in accordance with the invention in such a way that the gate device is arranged between a fuel separator and a fuel storage container, with the fuel delivery to the chamber of the gate device occurring pneumatically. It can similarly be provided that the gate device is arranged between a fuel separator and the combustion chamber of a furnace, so that direct charging of the furnace with the small-sized solid fuels occurs via the gate device in accordance with the invention.

Finally, the object underlying this invention is additionally achieved by a method of the kind mentioned above in such a way that the slide element of a gate device in accordance with the invention releases in a first position a filling opening arranged on a side of the chamber facing the fuel separator, the solid fuel is supplied in a preferably pneumatic way via the fuel separator to the chamber, thereafter the slide element is moved to a second position, with the filling opening being closed and an outlet opening opposite of the filling opening being released, so that a discharging of the chamber of the gate device occurs. As a result of the chamber size of the gate device, a dosed automatic charging of small-sized solid fuels, especially wood pellets, is advantageously achieved. This dosed charging also allows a verified control of the combustion process in the furnace.

The invention is now explained below in closer detail by reference to the drawings showing an embodiment that is not limiting in any way, wherein:

FIG. 1 shows a pneumatic conveying device according to the state of the art;

FIG. 2 shows a conveying device in accordance with the invention, with the gate device being shown in a filling position, and

FIG. 3 shows the conveying device of FIG. 2 with the gate device in a discharging position.

As is shown in FIG. 1, the filling of a fuel storage container attached to a heat generator for example occurs through a pneumatic conveying device 1, with solid fuel 3 in a pelletized or small-sized form being supplied from a fuel storage chamber 2 to a fuel separator 4. A rotary valve 5 is connected to the fuel separator 4, while the fuel 3 is transported via a spiral conveyor device 7 to a fuel storage container 6. The solid fuel 3 in the fuel storage container 6 is finally introduced into the combustion chamber of the furnace 8 via further spiral conveyor devices 7 for example. The rotary valve 5 acts here as an interruption element in order to prevent that hot combustion gases from the furnace 8 will reach the fuel separator 4 via the spiral conveyor devices 7 and subsequently the fuel storage chamber 2. The further conveyance of the solid fuel 3 merely occurs via spiral conveyor devices 7 arranged between the fuel separator 4 and furnace 8. This kind of charging is characterized by a high need for space and a complex and expensive configuration.

In contrast to this, the conveying device 10 in accordance with the invention and as shown in FIG. 2 is extremely compact and space-efficient. It is arranged entirely on a fuel storage container 20 and consists of a fuel separator 40, a gate device 50 situated beneath the same and a drive 60 required for the operation of the gate device 50.

Fuel separator 40 comprises a connection tube 41, through which conveying air is supplied to the device 10. The gate element 50 which is arranged on an outlet opening 42 of the fuel separator 40 comprises a filling opening 51, through which a chamber 52 of the gate device 50 is filled with solid fuel 3. The gate device 50 additionally comprises a slide element 53 which is movable along the longitudinal axis A of the gate device 50. For this purpose, the slide element 53 is in connection with a push-rod 54 which is in connection with the crank drive 60 via a connecting rod 61 (FIG. 3).

The gate device 50 is preferably arranged so as to sit in an oblique way on the fuel storage container 20, with the longitudinal axis A of the gate device 50 enclosing an angle α of approx. 450 with the longitudinal axis B of the fuel storage container 20. It has been noticed that a blockage of the outlet opening 56 of chamber 52 by blocking solid fuel 3 can be prevented.

FIG. 3 shows how the slide element 53 is moved from the filling position according to FIG. 2 to a discharging position, with a plate-like closing element 55 which is attached to the slide element 53 sealing the filling opening 51, while chamber 52 is displaced along the longitudinal axis A into the fuel storage container 20, so that the outlet openings 56 which are opposite of the filling openings 51 are released and the solid fuel is discharged into the fuel storage container 20.

A negative pressure generated by the pneumatic conveying device prevails in the fuel separator 40, so that as a result of minimal leakages in the gate device 50 or in the area of the outlet opening 42 which are the result of production tolerances for example, hot combustion gases can be sucked from the combustion device 8 to the fuel storage container 20. In order to prevent such suction, a venting valve 90 is provided which is arranged on the fuel storage container 20 and cooperates with the gate device 50 in order to enable pressure equalization in the fuel storage container 20. 

1. A gate device (50) for use in conveying devices (10) for the automatic supply of small-sized solid fuels (3), especially wood pellets, characterized by a chamber (52) which is movable by means of a slide element (53) between a filling position and a discharging position, comprising a filling opening (51) and an outlet opening (56), with the slide element (53) releasing the filling opening (51) for filling the chamber (52) with solid fuel (3) in the filling position while the outlet opening (56) is closed, and the slide element (53) closing the filling opening (51) in the discharging position while simultaneously the chamber (52) can automatically be discharged via the outlet opening (56) which is released in the discharging position.
 2. A gate device (50) according to claim 1, characterized in that a fuel separator (40) is arranged on the filling opening (51) of the chamber (52), which separator conveys the solid fuel (3) into the chamber (52) of the gate device (50).
 3. A gate device (50) according to claim 1, characterized in that a fuel storage container (20) of a furnace (8) is arranged on the outlet opening (56) of the chamber (52).
 4. A gate device (50) according to claim 3, characterized in that the longitudinal axis (A) of the gate device (50) intersects the longitudinal axis (B) of the fuel storage container (20) under an angle (α) of 35 to 60°.
 5. A gate device (50) according to claim 1, characterized in that the movement of the slide element (53) occurs through a crank drive (60).
 6. A gate device (50) according to claim 5, characterized in that the slide element (53) is connected via a connecting rod (61) with the crank drive (60).
 7. A conveying device (10) for the automatic charging of small-sized solid fuels (3), especially wood pellets, comprising a gate device (50) according to claim 1, characterized in that the gate device (50) is arranged between a fuel separator (40) and a fuel storage container (20), with the charging of fuel to the chamber (52) of the gate device (50) occurring pneumatically.
 8. A conveying device (10) for the automatic charging of small-sized solid fuels (3), especially wood pellets, comprising a gate device (50) according to claim 1, characterized in that the gate device (50) is arranged between a fuel separator (40) and the combustion chamber of a furnace (8).
 9. A method for the automatic charging of small-sized solid fuels (3), especially wood pellets, characterized in that a slide element (53) of a gate device (50) according to claim 1 releases in a first position a filling opening (51) arranged on a side of the chamber (52) facing the fuel separator (40), the solid fuel (3) is supplied via the fuel separator (40) to the chamber (52), thereafter the slide element (53) is moved to a second position, with the filling opening (51) being closed and an outlet opening (56) opposite of the filling opening (51) being released, so that a discharging of the chamber (52) of the gate device (50) occurs. 